The Gastec 127P p-Dichlorobenzene Detector Tubes are designed for sensitive, low-level measurement of p-dichlorobenzene (C6H4Cl2) in air using a compatible automatic air sampling pump.
The 127P provides a quantitative measuring range of 100 to 3,000 µg/m³, with a detection limit of 20 µg/m³ under the specified sampling conditions. The detector system produces a yellow-to-pale-reddish-purple color change for visual determination of p-dichlorobenzene concentration.
IMPORTANT: The Gastec 127P uses two connected tubes for each measurement. Each box contains 10 tubes for a total of 5 tests.
Automatic Air Sampling Pump Required
IMPORTANT: Gastec 127P p-Dichlorobenzene Detector Tubes require a compatible automatic air sampling pump capable of maintaining a continuous 100 mL/min sampling rate.
Correct Automatic Sampling Pump:
Gastec GSP-501FT Automatic Air Sampling Pump
The 127P is an automatic air sampling pump detector tube and should not be treated as a standard hand-pump detector tube.
Accurate measurement requires drawing 3,000 mL of air through the connected detector tube system at 100 mL/min for 30 minutes.
Do not substitute a standard manual Gastec detector tube pump for the required automatic sampling method.
Measurement & Sampling Specifications
| Measurement Range | Sampling Rate | Sample Volume | Correction Factor | Sampling Time |
|---|---|---|---|---|
| 100–3,000 µg/m³ | 100 mL/min | 3,000 mL | 1 | 30 Minutes |
The Gastec 127P requires a continuous sampling rate of 100 mL/min for 30 minutes, producing a total sample volume of 3,000 mL.
The correction factor is 1 under the specified sampling conditions. Temperature and atmospheric pressure corrections should be applied when required.
Product Specifications
Brand: Gastec
Tube Type: p-Dichlorobenzene Detector Tube for Automatic Air Sampling Pump
Part Number: 127P
Gas/Vapor Measured: p-Dichlorobenzene
Chemical Formula: C6H4Cl2
Measurement Range: 100–3,000 µg/m³
Detection Limit: 20 µg/m³ at 3,000 mL (minimum detectable concentration; not part of the quantitative measuring range)
Sampling Rate: 100 mL/min
Sample Volume: 3,000 mL
Correction Factor: 1
Sampling Time: 30 Minutes
Color Change: Yellow → Pale Reddish Purple
Operating Temperature: 5–35°C (41–95°F), temperature correction required
Operating Humidity: 20–80% RH, humidity correction not required
Relative Standard Deviation: 10% for 100–1,000 µg/m³; 5% for 1,000–3,000 µg/m³
Quantity: 10 Tubes
Tests per Box: 5 Tests
Shelf Life: 24 Months
Pump Requirement: Compatible Automatic Air Sampling Pump Required
Two-Tube Measurement System
The Gastec 127P requires two tubes to be connected together for each measurement.
The system consists of a primary tube and analyzer tube. The appropriate tube ends must be broken and the C-marked ends connected using the rubber tubing according to Gastec's instructions.
The analyzer tube is then connected to the automatic air sampling pump with its arrow pointing toward the pump.
Because two tubes are consumed during each measurement, one box containing 10 tubes provides 5 complete tests.
Always follow the official Gastec 127P instruction manual for proper tube preparation, connection, orientation, and sampling procedure.
Low-Level p-Dichlorobenzene Measurement
The Gastec 127P is designed for sensitive measurement of p-dichlorobenzene in the µg/m³ concentration range, making it suitable for environmental and residential air-monitoring applications.
The quantitative measuring range is 100 to 3,000 µg/m³.
The 20 µg/m³ detection limit represents the minimum concentration capable of producing a detectable reaction under the specified 3,000 mL sampling conditions. It is not part of the quantitative measuring range and should not be interpreted as a 20–3,000 µg/m³ measurement range.
During sampling, the detecting layer changes from yellow to pale reddish purple.
Common Applications
Gastec 127P p-Dichlorobenzene Detector Tubes may be used for applicable low-level monitoring applications including:
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Residential Environment Air Monitoring
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Indoor Air Quality Testing
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Environmental Air Monitoring
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Building & Facility Air Quality Investigations
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Low-Level p-Dichlorobenzene Monitoring
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VOC & Chemical Vapor Investigations
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Industrial Hygiene Applications
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Environmental Atmospheric Monitoring
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Laboratory & Research Applications
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Chemical Emission & Release Investigations
Temperature Correction
The Gastec 127P is designed for use between 5 and 35°C (41–95°F) and temperature correction is required.
The official Gastec 127P instruction manual provides a temperature correction table based on the detector tube reading and actual sampling temperature.
The specified operating humidity range is 20–80% RH, and humidity correction is not required within this range.
Atmospheric pressure correction may also be required according to Gastec's official measurement procedure.
Possible Interferences
Certain coexisting substances may affect Gastec 127P measurements.
Vinyl Chloride: May produce a positive interference and independently produce a pale reddish purple color.
1,2-Dichloroethylene: May produce a positive interference and pale reddish purple color.
Trichloroethylene: May produce a positive interference and pale reddish purple color.
Perchloroethylene: May produce a positive interference and pale reddish purple color.
Gastec identifies the following as producing no interference and no independent color change under the manufacturer's stated test conditions:
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Ammonia
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Hydrogen Chloride
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Chlorine
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Nitrogen Oxides
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1,1,1-Trichloroethane
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Aromatic Hydrocarbons
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Formaldehyde
Coexisting gases and vapors should always be considered when interpreting detector tube measurements.
Outdoor Measurement — Important
When performing an outdoor measurement, keep the Gastec 127P detector tubes out of direct sunlight during sampling.
Direct sunlight can affect measurement conditions, so the tubes should remain appropriately shielded throughout the sampling period.
Important
A compatible automatic air sampling pump is required for correct use of the Gastec 127P p-Dichlorobenzene Detector Tubes.
Purchase the Automatic Sampling Pump:
Gastec GSP-501FT Automatic Air Sampling Pump
Sampling is performed at 100 mL/min for 30 minutes, producing a total sample volume of 3,000 mL.
Two detector tubes must be connected for each measurement. Therefore, 10 tubes provide 5 complete tests.
Do not use a standard manual detector tube pump in place of the required automatic sampling method.
Temperature and atmospheric pressure corrections should be applied when required according to Gastec's official instructions.
For outdoor measurements, keep the detector tubes out of direct sunlight during sampling.
Always follow Gastec's official instructions for tube preparation and connection, sampling rate, sample volume, sampling time, temperature correction, atmospheric pressure correction, environmental conditions, possible interferences, and interpretation of results.
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